The present invention relates to a wind deflector for a vehicle with a deflector element that is mounted in a movable manner, and an actuator for moving the deflector element. The present invention further relates to a vehicle with a sliding roof and such a deflector element.
Under certain conditions a periodic pressure fluctuation occurs with hollow spaces which air flows against. This can be a problem with all vehicles. Vehicles are hereby not only meant to be passenger motor vehicles and heavy goods vehicles, but also for example airplanes and trains.
The pressure fluctuations in passenger cabins are noticed by so-called “rumbling noises”. These are extremely uncomfortable and disturbing for the passengers. So-called wind deflectors are, for example, often provided at the sliding roofs, which deflect the flow in such a manner that the pressure fluctuations in the passenger space are reduced. Rigid wind deflectors, however, only reduce the rumbling noises to a certain degree.
DE 197 50 218 C2 discloses a method for suppressing periodic pressure changes in a hollow space flown around by an outer flow and provided with a opening. A change of the flow direction of the outer flow opposed to current pressure change in the interior of the hollow space is effected periodically and in phase. Oscillating small deflecting wings are particularly used in phase for influencing the flow at the front edge of a roof section of a passenger motor vehicle. The wings deflect the flow at the upper roof side. Electric motors, piezo-ceramic actuators or electrodynamic actuators effect a deflection of the wings. A control cycle ensures that the deflection of the outer flow counteracts the pressure changes in the interior space.
It is disadvantageous with these wings that they have to be mounted to a curved axis, as the roof of a motor vehicle is usually curved. This curvature leads to problems with the wing movement.
Exemplary embodiments of the present invention are directed to a wind deflector that leads to reduced pressure fluctuations in a hollow space that is flown about, and which can be moved mechanically without problems.
This is achieved according to the invention by a wind deflector for a vehicle with a deflector element that is mounted in a movable manner and an actuator for moving the deflector element, wherein the deflector element can be moved in a linearly oscillating manner in one direction in space.
In an advantageous manner, the linear movement is independent of the curvature of the vehicle surface, and the deflector element can obtain the contour of the vehicle surface, so that optimum flow conditions can be achieved.
The wind deflector preferably has a center part and unmovable lateral parts, wherein the deflector element is arranged in a movable manner in the center part between the lateral parts. The movable deflector element in the center of the wind deflector is usually sufficient to achieve a high damping of the rumbling noises.
The center part can have a deflector base, to which the lateral parts are connected rigidly or in one piece, and on which the actuator is fastened. A relatively stable wind deflector can thereby be constructed.
According to a further embodiment, two hinge arms can be arranged in such a manner that they form a four bar hinge together with the deflector element and the deflector base. A stable movement amongst others orthogonally to the deflector base is thus possible with the deflector element.
Each of the two hinge arms can have a leaf spring. The four bar hinge is brought into a stable center position with these springs, around which the deflector element can oscillate.
Corresponding to an alternative embodiment, the wind deflector has a linear guide for the deflector element and a spring device for holding the deflector element in a basic position in the linear guide. An oscillating linear movement around a center position can also be realized hereby.
With this alternative embodiment, the spring device can comprise two spiral springs which are mounted to two opposite ends of the deflector element. The deflector element can be mounted symmetrically in a center position in this manner.
The actuator can be an electrodynamic actuator, whose elements can be moved in two orthogonal directions with regard to each other. The swinging movement of a four bar hinge can particularly be driven thereby.
According to a further embodiment, a further actuator can be present in addition to the actuator, and each of the actuators is connected to the end of the deflector element via a rocker. A mass balancing between the actuators and the deflector element can be achieved by this rocker construction. Accelerations introduced at the base thereby do not cause any relative movement of the deflector edge.
The deflector element can further have such a profile that a flow separation with regard to the inflow takes place at a rear edge. This has the advantage that smaller flow speeds occur at the deflector edge and flow swirls can hardly still impinge on the deflector element, whereby the noise disturbance by the air inflow is reduced further.
A vehicle with a sliding roof is provided according to a preferred embodiment, at which the above-described wind deflector is mounted. Rumbling noises in the passenger space can be reduced with it in a particularly effective manner.